How small can a server be?

[Drocona]

Depending on what happens in the server, you should be able to get 24, but when it gets real busy at some times you might start to experience some lag. 20 players should be safe.

Also running a fast download server from the same connection as the gameserver is running is NOT smart at all, it will either suck up all bandwidth from the gameserver or it will be just as slow as the normal server download method. the sv_downloadurl really has to be in a different place.